Recently something has gone wrong with our website so that whenever you try to access an aspx file, it shows the following error:

Server Error in '/RALSWeb' Application.

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

I have a webdatagrid control that is loaded by using an sqldatasource. I have add and edit methods that behave correctly, however, I have a problem when I delete a row. I can delete the row correctly from the datagrid and the database, but as soon as I select another row in the grid straight after, I get an error:

Microsoft JScript runtime error: 'undefined' is null or not an object

There are no events wired up to the row select, so it doesn't appear to be that.